Didn't you recover and remove the suspected foreign object from its watery ditching point? Surely a jam jar could have played a useful part in this exercise in space style recovery and you could then have whipped it gingerly round to your local path lab for analysis. A brown glass jar would have been your best choice as a storage unit for then, apart from the reasonably obvious camouflage benefits, no direct light could have contaminated the purity of your expulsive excrement.